Shadow Complex Remastered

Don't be scared by the high TA ratio, this one only has a handful of tricky spots in it. I did it in a little over an hour. If your struggling with any part then feel free to message me or comment and I'll help out.
This solution will take some time but I'll update it as I replay the challenge levels. The only one I really had any problems with was the last one so in the meantime I'll give ya some tips for that.
The Big One: you can kill the mech being just out range so you see him n he doesn't see you, just blast away with regular ammo. Aim for headshots on the grunts and jump n jetpack down on them to make it easier to get them. Try to stick to the high ground generally. Be very conservative with your health. There is a health pack right in front of you at the start, and another behind you, I recommend saving those till your 50 health for the 1st one and then when you get low go get the 2nd one. Take your time n don't rush through it. Remember whenever you pickup a health/ammo upgrade it not only extends your current health/ammo but also fills it completely up, use that strategically to your advantage.